JPH09314931A - Printing scanning mechanism for paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing mechanism with minimum printing margins. SOLUTION: An image receiving sheet 12 to be printed is fed from the left side in the figure, and moved forward on an endless belt 21 until it is sensed by a sensor 11. (At that time, a thermal head 6 is in the released state). The start of paper feeding is carried out by the slight pressure welding pressure of a paper feed pressure welding roller 17. The paper feed pressure welding roller 17 is an easily deformable material such as a foaming material or the like, and 17' in the figure is set as a rotatable fixed support. When the paper 12 is moved to a pressure welding component 19, the movement of the paper 12 is carried out dominatively by the moving force formed by multiplying the pressure welding force between the paper and a supporting component 31 by the friction coefficient between the paper 12 and the endless belt 21. The pressure welding force is determined by a tension spring 20. The circumference of a grip roller for moving the paper 12 heretofore available is replaced by the belt 21 to form a plane, and the pressure welding component 19 using a small diameter roller is provided in the vicinity of a heater of a head to reduce the printing margins to L'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print scanning mechanism for a sheet, and more particularly to an image receiving sheet scanning mechanism for a printer equipped with a line type thermal head, and more particularly to color printing while reciprocally scanning the sheet in a frame sequential manner. The present invention relates to a print scanning mechanism used in a printer that performs printing.

[0002]

2. Description of the Related Art FIG. 5A is a schematic configuration diagram of a main part for explaining a conventional print scanning mechanism. In the figure, 1 is a grip roller, 2 is a pinch roller, 3 is a paper scanning motor, and 4 is a sheet scanning motor. A thermal head, 5 is a recording unit, 6 is a driver mounting unit, 7 is a platen roller, 8 is a head pressure contact / release arm, 9 is a cam, 10 is a motor, 11 is a recording position detection sensor, and 12 is an image receiving paper. The example shown in FIG. 5A shows a reciprocal printing scanning method using a grip roller. As shown in the figure, the distance L between the grip roller 1 and the recording portion 5 of the recording head 4 is L.
Becomes a non-printed area.

FIG. 5B is a view for explaining an example of a conventional technique for minimizing the non-printing area shown in FIG. 5A, in which 13 is a front grip roller and 14 is a front grip roller. Is a front roller drive motor, 15 is a rear grip roller, 16 is a rear roller drive motor, and the other parts having the same functions as those in FIG. 5A are the same as those in FIG. 5A. Reference numbers are attached. As in this example, 2 before and after the head
A method has also been proposed in which one grip roller 13 and 15 is provided and the image receiving paper 12 is moved alternately or at the same timing, but this method is adopted only for transfer to a high-rigidity card. .

[0004]

When the two grip rollers as shown in FIG. 5B are used, the image is received at the first movement (until the right roller 15 prints and the left roller 16 meshes). If the paper 12 is not rigid, it may buckle and become a jam (therefore, as described above, it is limited to the high-rigidity card). Further, it is difficult to completely match the roller peripheral speeds to each other even in a section where printing is performed by both rollers, and a simple mechanical structure causes development such as jitter.

The present invention has been made for the purpose of solving the above-mentioned problems of the prior art and providing a printing mechanism which minimizes the printing margin.

[0006]

According to a first aspect of the present invention, in a direct color type or transfer type printer using a line type thermal head, an image is received on an endless belt which is rotatably wound including a platen roller. It is characterized in that the paper is held and scanning is performed.

According to a second aspect of the invention, in the first aspect of the invention, a pressure contact member for holding the image receiving paper on the endless belt is provided in the vicinity of the heating element of the thermal head.

According to a third aspect of the invention, in the first or second aspect of the invention, the driving of the endless belt is performed by another driving roller provided at a position different from the platen roller. Is.

According to a fourth aspect of the invention, in the third aspect of the invention, a part or the whole of the circumference of the driving roller is subjected to grid particle forming processing or silicone film coating for preventing slippage with the endless belt. It is characterized by being rubbed.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the drive that meshes with the concavo-convex tooth profile provided on the endless belt at two positions outside the printing width of the image receiving paper, which is a part of the circumference of the drive roller. The feature is that a tooth profile is provided.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the endless belt is made of a rubber material portion having elasticity and a high friction coefficient, and a resin sheet or a metal or fiber material supporting the rubber material portion. It is characterized by comprising a support material portion and a slip prevention portion for preventing slippage with the drive roller.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(Inventions 1 and 2) FIG. 1 is a side view of a printer including an endless belt according to the present invention, a drive roller of the endless belt, and a pressure contact member for holding a sheet on the endless belt. Among these, 17 is a pressure contact roller for paper feed, 18 is an arm, 19 is a pressure contact member, 20 is a tension spring, 21 is an endless belt, 22 is a drive roller, 23 is a platen roller, 24
Is a deceleration mechanism, 25 is a motor, 31 is a receiving member, and other parts having the same operations as in the prior art shown in FIG. 5 are denoted by the same reference numerals as in FIG.

In FIG. 1, the image receiving paper 12 to be printed is fed from the left side in the drawing, and advances once until it is detected by the sensor 11 on the endless belt 21 (at this time, the thermal head 6 is in the released state). The feeding is started by a slight pressure contact pressure of the pressure roller 17 for feeding. In this case, the paper feed pressure contact roller 17 is made of an easily deformable material such as a foam material, and 17 'is set as a rotatable fixed fulcrum. When the sheet 12 moves to the press contact member 19,
The movement of the paper 12 is predominantly performed by the moving force obtained by multiplying the pressure contact force with the receiving member 31 and the friction coefficient between the paper 12 and the endless belt 21. The pressure contact force is determined by the tension spring 20.

As noted above, the present invention has traditionally used paper 12
The circumference of the grip roller 1 which has been moved is replaced with the belt 21 to form a flat surface, and the press contact member 19 using a small diameter roller is provided in the vicinity of the heating element of the head. It became possible to reduce to.
Further, the printing is performed by using a belt interposed between the platen and the platen as a receiving material. The pressure contact member 19 does not necessarily have to be in the shape of a roller, and may be a resin plate having good slipperiness or a coated metal.

(Invention of Claim 3) A dedicated drive roller 22 is used to move the endless belt 21 at a prescribed linear velocity. The driving accuracy of the drive on the platen roller 23 side becomes unstable due to the following reasons, and a jitter or the like is likely to occur in the printed image quality. Reason: The rubber hardness (40 to 50 degrees) necessary for head pressure contact for determining the printing quality and pressure deformation that are incompatible with the belt driving condition or slippage is meaningless. Therefore, the dedicated drive roller 22 is provided, and the platen 23 is rotated together.

(Invention of Claim 4) The outer diameter is determined in consideration of the thickness of the endless belt and the paper so that the linear velocity of the paper becomes a specified value. Further, as shown in FIG. 2 (A), a protrusion 22a is formed on a part or all of the surface of the drive roller 22 so as not to slip with the inner side surface of the endless belt, and the slip is caused by a slight protrusion at the tip. To prevent this, as shown in FIG. 2B, the material 22b having a high friction coefficient is applied thinly. As the method of FIG. 2A, there are a method of spraying alumina and a method of fixing zirconia particles having a diameter of several tens to several hundreds μm with an adhesive. On the other hand, as a method of FIG. 2B, there is a method of coating a high friction material such as silicone in a film shape.

(Invention of Claim 5) In order to realize more reliable meshing transmission with respect to the belt movement by a certain kind of friction transmission shown in the invention of Claim 4, as shown in FIG. It is effective to provide the drive roller 22 with the uneven tooth profile 26 that meshes with the tooth profile 27 provided on the drive roller 22. The concavo-convex tooth profile 26 may be a mini-pitch with a pitch of about 1.5 to 50 of the tooth profile 27 used for the normal transmission belt 21, and the tooth profile may be a trapezoid, a triangle or a half circle. As shown in the drawing, it is provided on both side edges outside the width of the image receiving paper 12 to eliminate the influence of printing.

(Invention of Claim 6) FIG. 4 is a side view of an essential part showing the structure of an endless belt. In the figure, 28 is an elastic layer, 29 is a support layer, 30 is an anti-slip layer, and the elastic layer 28 is In addition, it is a material with a high coefficient of friction for moving the paper, and at the same time, it is necessary for good printing by head pressure, that is, it is necessary to achieve good heat transfer without air gaps. The hardness to obtain the contact pressure is obtained.

The support layer 29 is made of a material such as urethane rubber or nylon woven cloth, which has little elongation and deformation and is strong against repeated bending. Anti-slip layer 30
Forms a hard urethane layer that is processed to accurately transmit the rotational movement amount of the driving roller 22 and to obtain a driving force enough to rotate the platen roller. When the meshing drive method is performed, it is preferable to form the uneven tooth profile according to the fifth aspect.

[0020]

As is apparent from the above description, according to the present invention, the image receiving paper is held on the endless belt that is rotatably wound including the platen roller, and the printing scanning is performed. Further, since the pressure contact member for holding the image receiving paper on the endless belt is provided in the vicinity of the heating element of the thermal head, it is possible to realize the printing mechanism which minimizes the printing margin.

Further, the endless belt is driven by another drive roller provided at a position different from the platen roller, and further, the endless belt is slipped on a part or the whole area of the circumference of the drive roller. In order to prevent this from occurring, grid particles are formed or a silicone film is coated, or the tooth profile is provided on the endless belt at two locations outside the print width of the image receiving paper that are part of the circumference of the drive roller. A drive tooth profile that meshes with the endless belt is provided, and further, a rubber material part having elasticity and a high friction coefficient for the endless belt, a support material part made of a resin sheet or a metal or a fiber material for supporting the endless belt, and the drive roller are slid. Since it is configured with a slip prevention unit that prevents the sheet, the sheet can be conveyed accurately and reliably.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram for explaining an example of a print scanning mechanism for a sheet according to the present invention.

FIG. 2 is a side view for explaining an example of a drive roller.

FIG. 3 is a perspective view of a main part for explaining a relationship between a drive roller and an endless belt.

FIG. 4 is a side view of an essential part showing the structure of an endless belt.

FIG. 5 is a diagram for explaining an example of a conventional print scanning mechanism.

[Explanation of Codes] 1 ... Grip roller, 2 ... Pinch roller, 3 ... Paper scanning motor, 4 ... Thermal head, 5 ... Recording unit, 6 ... Driver mounting unit, 7 ... Platen roller, 8 ... Het pressure contact / release arm, 9 ... Cam, 10 ... Motor, 11 ... Recording position detection sensor, 12 ... Image receiving paper, 13 ... Front grip roller, 1
4 ... Front roller drive motor, 15 ... Rear grip roller,
16 ... Rear roller drive motor, 17 ... Feed roller pressure contact roller,
18 ... Arm, 19 ... Pressure contact member, 20 ... Extension spring, 21
... endless belt, 22 ... drive roller, 23 ... platen roller, 24 ... reduction mechanism, 25 ... motor, 28 ... elastic layer, 2
9 ... Support layer, 30 ... Anti-slip layer, 31 ... Receiving member.

Claims (6)

[Claims] 1. A direct color type or transfer type printer using a line type thermal head, wherein an image receiving paper is held on an endless belt which is rotatably provided including a platen roller so that printing scanning can be performed. A print scanning mechanism for paper, which is characterized in that 2. A print scanning mechanism for a sheet according to claim 1, further comprising a pressure contact member for holding an image receiving sheet on an endless belt, in the vicinity of a heating element of said thermal head. 3. The driving of the endless belt is performed by another driving roller provided at a position different from the platen roller.
A print scanning mechanism for the paper described in. 4. A grid particle forming process, a silicone film coating, or the like is applied to a part or the whole area of the periphery of the drive roller so as to prevent slippage with the endless belt. A print scanning mechanism for the paper described in. 5. A drive tooth profile that meshes with the concave-convex tooth profile provided on the endless belt is provided at two locations outside the print width of the image receiving paper, which are part of the circumference of the drive roller. Item 3. A print scanning mechanism for a sheet according to item 3. 6. The endless belt is prevented from slipping between a rubber material portion having elasticity and a high friction coefficient, a support material portion made of a resin sheet or a metal or a fiber material for supporting the rubber material portion, and the driving roller. 6. The paper print scanning mechanism according to claim 1, wherein the paper print scanning mechanism comprises a slip prevention unit.